Up, Underground and Through
by Trey the Lone Wolf
Summary: What if... theoretically. Bonnie and Trey fell into a mountain? What if... Flowey was spared? What if... Determination wasn't enough? But hey, that's just me being theoretical. Right...? (Very confusing I know...)
1. The Spring - Ch1

**Hi guys! This is the story I spoke of. The Undertale x FNAF. I hope you enjoy it. This is one isn't written down anywhere so it's all your choice as to how the story moves on. Kinda like Undertale. I hope I can make a decent story and actually finish it this time. So umm… On with the show…? I suppose… I can't run a show very well…**

 **Mettaton: Oh yeahhhhhh…**

 **Oh god… Run. Just start reading please.**

Trey balanced on a log as Bonnie watched and walked along side him. "Careful Trey." he warned with a smile. The boy nodded.

"I heard there is a spring, like a hot spring, at the top of the mountain." he told the purple bunny.

"Well… I suppose we can go… But not for too long. You know what happen to me last time I didn't have you back in time. Chica will have my ears personally removed." he said, touching one of his ears. The climb was rather simple for Bonnie however the same could not be said for Trey. Bonnie watched him struggle for some time.

"So... high up…" he said before being plucked from the ground and onto Bonnie shoulders'.

"You're gonna pass out at that rate." he chuckled as he broke out into a sprint.

"You're probably right." Trey agreed. After they made it to the top and Trey was set down, they looked at the spring.

"It looks weird." the bunny said while the boy got closer to touch it.

"It's not a spring…" he proclaimed. The crater was decorated with vines. The bottom far, far below didn't seem to have any wet spots from the water in the crater. The water hovering as if there was a net, allowing very few drops of water to cascade down to a patch of yellow nouns. A simple touch from him caused a temporary ripple. Bonnie reached out for Trey as he kneeled down to try to touch the bottom.

"How…?" he mumbled as he hand reached open air on the other side of the water.

"Trey…" Bonnie said in a warning manner. He grabbed the hood of Trey's jacket while he leaned over more, knowing Bonnie had his hood.

"It's fine… But what's that…?" he said. The crumbling ground was slowly giving away but the soft dirt and shifting water kept Trey from hearing it's sounds. However Bonnie heard it and knew it was coming.

"Trey! Move now! It's break-" he started as the ground broke behind them both and they fell down into the crater. Bonnie looked around rapidly while spinning in the air. He looked for Trey who was nothing short of terrified.

"Bonnie! Bonnie! Bonnie help!" he called out. Bonnie tried to reach Trey and snagged his foot, curling up to protect the boy. Seconds turned into minutes as they continued to fall. Soon they both opened their eyes to see a huge fan under them. They both looked at the fan blankly. Bonnie let the boy go and Trey flew on over to the side of the fan where he landed and found a note.

"Good job nerd. You fell into the trap of the great Popeyerus…? Papyrus. And Undyne." he read as Bonnie stood next to him to read the note. Trey looked up. It wasn't a long drop but it surely wasn't one to climb back up. Looking behind him, he assumed the only way out was onward.

"Where are you going?" Bonnie said, watching him go into the dark hallway.

"Home."

"How?! We have no clue as to where we are." he said, running after him.

"Only one way to find out." he continued down the hall. Bonnie sighed and followed. The boy soon stopped and peered into the darkness. "What's up?"

"What's that yellow thing?" Trey asked.

"Howdy!"

 **It's short. I know. But I wanted to leave the cliff hanger and I also didn't wanna pour too much into it and not know where to go next or how you guys would feel about it. Reviews truely help. It's hard being a YouTuber and Author. But someone has to make it work.**

 **Mettaton: Ooo! Fancy…**

 **Mettaton… Please…**

 **Mettaton: -Gives Trey his signature television smile-**

 **...**


	2. The Ruins and a Few Guests - Ch2

**Let's clear something up here. The time period. It's after the True Pacifist route. Even with the option to leave, Frisk convinces them to come back to live in the Underground. But since everyone was consumed during the Hopes and Dreams fight. No one knows who Flowey is except Frisk. Hope that helps you put in the rest of the puzzle pieces. If you have anymore questions. You know where to ask!**

"Ello…" Trey said, cautiously.

"You're new here, aren't ya?" the yellow entity pressed on. Bonnie moved Trey back slightly.

"Yeah… You could say that…" Bonnie asked.

"Well someone better teach ya about how things work down here! I guess little ole me will do." he said with a slight demonic smile.

"Okay." Trey said. He watched the flower.

"Alright! Now this. This is a friendliness pellet… You got to catch all of the-" the flower was stopped short by a female goat.

"Stop it! Darn flower…" giving the flower a cold glare. Bonnie looked at the pair like Trey, who was vastly confused.

"Oh my fazbear! Please stop! What is happening here?! Who are you!?" Bonnie yelled.

"Oh. Sorry my child and my… pet…" the goat said, getting a purple bunny glare in response. "I am Toriel. The caretaker of the ruins."

"I'm Flowey…" he said, quietly. Toriel turned to criticize him more but he disappeared into the ground.

"Horrid creature…" she said. The pair just looked at her as she mumbled to herself about mean creatures and butterscotch pie.

"So…" Trey said, hoping to regain her focus.

"Oh yes! Hello! I assume you're lost. I wish to help you get back home. It's really simple. Follow me please!" she said, turning to leave to the dark cave. Bonnie looked at Trey.

"Should we follow?" the bunny asked.

"Only one way to find out!" he repeated with a smile, as he ran to Toriel and did a couple circles around her, while she giggled about him being a silly child.

"You said that last time and we ran into a goat and flower…" he mumbled as he followed, keeping an eye on Toriel. The two emerged through a door to a room with stone pressure pads. And a door. A heavy door. One that was very locked.

"The ruins is full of many puzzles." she stepped on certain pads and the door swung open. "Let's go to the next room."

Trey groaned as she left, causing Bonnie to pet his head. "What's the matter?" he asked with a slight frown.

"I'm learning…" he said with closed eyes. Bonnie smiled.

"You've gotta learn something eventually. We're somewhere completely new." he replied. "Now let's keep up with goat lady."

"Alright." they both moved into the next room with a couple streams and a few levers. "Do I have to go swimming…? I can't swim…" he said, with fear as he hugged the side of Bonnie. "Don't make me swim!" he cried out, putting his face into Bonnie's furry side.

"I won't make you swim…" Bonnie smiled as he pet him again.

"No no child. Just pull the levers." Toriel giggled a bit at his cute reaction. "But I labeled them for you so you don't have to fret again."

"Okay…" he wiped away a single tear then walked over to the levers and saw the labels Toriel must have set. "What happens if I don't pull them?" he said, turning to Toriel.

"You have such a curiosity." she said with a smile.

"I do and I wanna know the consequences of every action." he replied.

"If you don't hit the switch, we'll just stay here because the spikes are blocking our path."

"Oh okay…" he said as he flipped the lever that instructed you not to flip this one. It did nothing.

"I clearly marked the right one." she smiled. "This is only a test luckily."

"Oh… Guess I failed then." he said with slight disappointment, flipping the correct lever this time. As a reward of his good obedience, the spikes dropped into the ground.

"We could have swam across." Bonnie commented. "I would have carried you over."

"But he wouldn't have learned anything from it…" Toriel said, glaring.

Trey looked at Bonnie then Toriel, sensing some tension. He was very uncomfortable with this situation. But his attention was captured by a dummy right the corner. Slipping past Toriel, he examined it. It looked like an animal or monster. Not human like at all. It was safe to assume Tori put it here. Another test for future preparation. But why a dummy. Nothing besides that flower looked evil enough to attack. So who would need to practice fighting? Toriel walked up behind Trey and smiled a bit, saying "You've found the dummy."

He nodded. "Why is it here? Do I have to fight things?"

"No no no child." she shook her head. "Down here there are far too many monsters that could hurt you. I want you to talk to the dummy."

Trey as well as Bonnie, who was calmly leaning on the wall adjacent to the two, looked at her for a moment. Dumbfounded, he tilted his head a little and turned towards the dummy. It was a slight challenge to do so, he started wondering who was the real dummy here. Feeling weird, he spoke to the lifeless body.

"H-hello? You… You look rather good today." he said.

"T-that's the nicest thing anyone has ever said to me…" it replied.

"No prob-" he stopped short with widen eyes.

"No really… That was so nice of you…"

"B-b-b-b…"

"Pardon me?"

"Bonnie!" he shrieked as he ran behind his favorite animatronic.

"It's alright Trey…" he said to reassure him.

Tori and Dummy were calm as they looked at the pair.

"I realize I don't know too much about you." Tori said to Bonnie. "But you must have some relationship to the child."

"I do. He's a good friend." he replied.

"Well. We can discuss more later." she handed Bonnie something.

"What's this for?"

"It's a cell phon-"

"No thank you." Bonnie said, handing it back. Hearing the word phone was a bit of a trigger word when it came to dealing with children or friends, in Trey's case.

"But how am I to talk to the ch-"

"No. Thank you." he said, taking pauses to emphasize his position on the matter. Trey looked at Tori. She was cross, probably didn't know how to handle this situation. It seemed new to her. She took a deep breath.

"Very well." she said, accepting the phone.

"Now. Where are we headed now?" the bunny said with little patience. Tori looked at him, giving things great thought.

"Prove to me you're strong enough." she said, glaring as she turned away and started walking.

 **Mettaton: Ooo drama!**

 **Quiet you. So I soon realized two things. One. I'm just replaying the game in text. And Two. There's not enough FNAF related things going on. So let's kick it into third gear and actually get to the fan fiction.**

 **Mettaton: Third gear like the chapter number. How punny!**

 **._.**


End file.
